34.76
o
, nearly.
Explanation:
Angle of elevation = arc tan( (vertical height)/(length os the shadow)).
Here, this angle is
arc tan (12.5
/
18) =
34.78
o
, nearly
you will need to use the law of cosines since this picture does not indicate that this is a right triangle
c^2 = a^2 + b^2 – 2ab cos C,
16^2 = 17^2+8^2 -2*17*8*cosC
256=289-272cosC
-33=-272cosC
33/272 = cosC
cos^-1 (33/272)=C taking the inverse cos
C=83.0 (to the nearest tenth)
b^2 = a^2 + c^2 – 2ac cos B,
8^2 = 17^2 +16^2 -2*17*16cosB
64=289-544cosB
-225=-544cosB
225/544=cosB
cos^(-1) =B
B=65.5
A=180-83-65.6
A=31.4
77 days turned into weeks means that you have to divide by seven.
77/7 = 11.
It took eleven weeks to plan (Answer choice D)
